TAMPA, Fla. (AP) — It may have been a partisan barb from a Democrat, but Los Angeles Mayor Antonio Villaraigosa's pointed criticism of the array of Hispanic speakers at the Republican National Convention laid bare a truth that could hurt the GOP: Mitt Romney is having a tough time winning over Latino voters.

"You can't just trot out a brown face or a Spanish surname and expect people are going to vote for your party or your candidate," Villaraigosa, a U.S. born-Latino and chair of the Democratic National Convention, told reporters Tuesday. He was referring to Republican plans to give airtime this week to prominent Latino Republicans, such as Sen. Marco Rubio of Florida.

"Window dressing doesn't do much for a candidate. It's your policies, your platform. This is a party with a platform that calls for the self-deportation of 11 million people," he said, referring to the estimated number of illegal immigrants living in the U.S.

Romney campaign senior adviser Danny Diaz characterized Villaraigosa's comments as "divisive." He said they were part of the increasingly personal attacks by President Barack Obama's campaign that are designed to distract voters from the struggling economy.

"We are very confident that once our story is told, the vast majority of voters will pull the lever for Gov. Romney, and that we will include strong support from Latino voters," Diaz said.

Prominent Latino speakers at the Republican convention include Rubio, who is set to introduce Romney on Thursday; New Mexico Gov. Susanna Martinez; Rep. Francisco Canseco of Texas; Sher Valenzuela, the Republican candidate for lieutenant governor of Delaware; Nevada Gov. Brian Sandoval; and Ted Cruz, GOP Senate nominee from Texas.

Latino voters could make the difference for both Obama and Romney, given that the election will probably hinge on swing states with large Hispanic populations, such as Florida and Colorado, and is expected to be close. Some 12.2 million Hispanics are expected to vote this November, according to projections by the nonpartisan National Association of Latino Elected and Appointed Officials.

Latinos heavily supported Obama in 2008, and Romney has made efforts to court them in hopes of winning a larger share of their votes. Earlier this summer, Obama was outspending Romney in advertising directed at Spanish-speaking Latinos. Both campaigns are also posting ads on the Web.

This week, the Romney campaign released a Spanish-language television ad, "Juntos (Together)," in which Romney speaks in English and his words are translated into Spanish with subtitles. The campaign also released a 60-second radio ad this week featuring Romney's son, Craig, speaking in Spanish.

Romney's campaign has said it is aiming for 38 percent. On Tuesday, Villaraigosa estimated Democrats would get about 70 percent of Latino voters.

There is no shortage of ideas on why Romney is struggling.

In an open letter to the GOP published last week, Univision news anchor Jorge Ramos told Republicans they will lose the Hispanic vote in November and "might be condemned to lose the White House for many decades" due to positions such as Romney's opposition to legalization for undocumented immigrants and his push for self-deportation, an idea that people who are in the country illegally might leave the U.S. on their own if life is made difficult enough for them.

Ramos, who broadcasts in Spanish and is one of the most watched anchors in the United States and across Latin America, said Republicans have squandered commonalities with Hispanics, such as opposition to big government and abortion, and instead made themselves enemies of immigrants.

It's a sentiment shared by Guy Sideboard, who was born in Puerto Rico and moved to Tampa as a boy.

"As a Latino, I believe in hard work," said Sideboard, a bilingual information technician. "But there are many Latinos who don't have many opportunities, and I don't think Romney can relate to them at all."